You may have noticed that the QuickStart guide (page 10), is missing steps for Exchange 2016:
Deploying the Administration Service > Configuring the Administration Service account > Access to Exchange Organizations
This is a documentation defect (TF00744178).
Please follow the steps mentioned for Exchange 2013 as they are exactly the same for Exchange 2016.
Active Roles 7.2 - Quick Start Guide (Configuring the Administration Service account)
This will be fixed on a future release of the product.